创建一个表：mysqlgt; CREATE TABLE students (-gt; sno CHAR(10) PRIMARY KEY,-gt; sname CHAR(8) NOT NULL,-gt; ssex CHAR
创建一个表：
mysql> CREATE TABLE students (
-> sno CHAR(10) PRIMARY KEY,
-> sname CHAR(8) NOT NULL,
-> ssex CHAR(1) NOT NULL CHECK(ssex = 'F' OR ssex = 'M'),
-> sage INT NOT NULL,
-> sdept CHAR(20) DEFAULT 'Computer'
-> )
-> ;
MySQl所支持的字符类型：
修改表结构：
mysql> ALTER TABLE students CHANGE sage sage INT UNSIGNED;
mysql> ALTER TABLE students ADD Grade1 INT NOT NULL DEFAULT '1';
删除一个字段：
mysql> ALTER TABLE students DROP Grade1 ;
表重命名：
mysql> ALTER TABLE students RENAME students2;
数据库存储引擎类型：
存储引擎：相当于一个插件，，MySQL跟存储在磁盘上的文件进行交互的接口。
*************************** 1. row ***************************
Engine: InnoDB（行级别锁 粒度比较小）
Support: YES
Comment: Supports transactions, row-level locking, and foreign keys
Transactions: YES
XA: YES
Savepoints: YES
*************************** 2. row ***************************
Engine: MRG_MYISAM
Support: YES
Comment: Collection of identical MyISAM tables
Transactions: NO
XA: NO
Savepoints: NO
*************************** 3. row ***************************
Engine: BLACKHOLE
Support: YES
Comment: /dev/null storage engine (anything you write to it disappears)
Transactions: NO
XA: NO
Savepoints: NO
*************************** 4. row ***************************
Engine: CSV
Support: YES
Comment: CSV storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 5. row ***************************
Engine: MEMORY
Support: YES
Comment: Hash based, stored in memory, useful for temporary tables
Transactions: NO
XA: NO
Savepoints: NO
*************************** 6. row ***************************
Engine: FEDERATED
Support: NO
Comment: Federated MySQL storage engine
Transactions: NULL
XA: NULL
Savepoints: NULL
*************************** 7. row ***************************
Engine: ARCHIVE
Support: YES
Comment: Archive storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 8. row ***************************
